Tanner crabs living on the seafloor of the northeast Pacific Ocean may be adaptive to climate change, according to a recent study by the University of Victoria’s Ocean Networks Canada and the Oregon State University.
The crabs were originally thought to exclusively eat phytoplankton until researchers observed them snacking on methane-filled bacteria about 1.2 km deep in B.C.’s oceans.
“Evidence shows the crabs’ diet is diverse and includes bacteria that processes methane,” said Fabio De Leo, co-author of the study and senior scientist at the University of Victoria’s Ocean Networks Canada, in an emailed statement.
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“This suggests that their populations may be able to adapt if their common food source becomes scarce. By studying and collecting these specimens, we can learn how a variety of sea-dwelling species are adapting to ongoing changes linked to climate change.”
The crabs were observed near methane seeps, also known as cold seeps, which are continental-margin areas where methane comes up from the ocean floor.
Researchers observed the unusual sight of a Tanner crab flipping up on its chest – near the seep due to methane build –so they collected specimens and found biochemical markers in the crabs’ muscles, stomachs and tissues.
Researchers also observed the crabs migrating, suggesting that Tanner crabs could be forwarding methane-based food energy to other seafloor-dwelling species.
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“The thinking used to be that the marine food web relied almost solely on phytoplankton dropping down through the water column and fertilizing the depths,” says Andrew Thurber, a marine ecologist at Oregon State University and co-author on the study. “Now we know that this viewpoint isn’t complete and there may be many more facets to it.”
The study began in 2012 and findings were recently published in the Frontiers in Marine Science magazine.
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